tailieunhanh - Báo cáo khoa học: From meiosis to postmeiotic events: Homologous recombination is obligatory but flexible

Sexual reproduction depends on the success of faithful chromosome trans-mission during meiosis to yield viable gametes. Central to meiosis is the process of recombination between paternal and maternal chromosomes, which boosts the genetic diversity of progeny and ensures normal homo-logous chromosome segregation. | ỊFEBS Journal MINIREVIEW From meiosis to postmeiotic events Homologous recombination is obligatory but flexible Lóránt Szekvolgyi and Alain Nicolas Recombination and Genome Instability Unit Institut Curie Centre de Recherche UMR 3244 CNRS Universite Pierre et Marie Curie Paris France Keywords double-strand break histone modification recombination sister chromatid cohesion Spo11 Correspondence A. Nicolas 26 rue d Ulm 75248 Paris Cedex 05 France Fax 33 0 1 56 24 66 44 Tel 33 0 1 56 24 65 20 E-mail Received 12 September 2009 revised 9 November 2009 accepted 17 November 2009 doi Sexual reproduction depends on the success of faithful chromosome transmission during meiosis to yield viable gametes. Central to meiosis is the process of recombination between paternal and maternal chromosomes which boosts the genetic diversity of progeny and ensures normal homologous chromosome segregation. Imperfections in meiotic recombination are the source of de novo germline mutations abnormal gametes and infertility. Thus not surprisingly cells have developed a variety of mechanisms and tight controls to ensure sufficient and well-distributed recombination events within their genomes the details of which remain to be fully elucidated. Local and genome-wide studies of normal and genetically engineered cells have uncovered a remarkable stochasticity in the number and positioning of recombination events per chromosome and per cell which reveals an impressive level of flexibility. In this minireview we summarize our contemporary understanding of meiotic recombination and its control mechanisms and address the seemingly paradoxical and poorly understood diversity of recombination sites. Flexibility in the distribution of meiotic recombination events within genomes may reside in regulation at the chromatin level with histone modifications playing a recently recognized role. Introduction The means by which sexual reproduction emerged .